FIG. 6.

Effects of expression of wild-type or mutant Akt on the frequency of TUNEL-positive cells during myogenic differentiation. Differentiating myocytes were transfected with plasmids encoding wild-type, constitutively active, or dominant-negative Akt tagged with HA. The plasmid encoding β-Gal (β-gal) was used as a control. After transfection, cells were incubated in growth medium for 18 h and then in DMEM containing 0.5% horse serum for 24 h. Transfected cells were identified by immunostaining with anti-HA or β-Gal antibodies. Apoptotic cells were detected by TUNEL (TNL). (A) Representative photomicrographs showing TUNEL-positive cells (arrows). Cells were treated as described above and stained by TUNEL (TNL; green), Hoechst 33342 (Hoechst; blue), and anti-HA or β-Gal antibody (HA or β-gal; red). (B) Percentage of cells that stained positive for plasmid-encoded transgene expression. For each condition, four separate cultures were transfected with the indicated plasmid, and at least 50 HA- or β-Gal-positive cells were counted on each plate. Data are shown as mean ± SEM.